63262-06-6

106-37-6

63262-06-6

General procedure for the synthesis of 1,4-dibromo-2,5-diiodobenzene from 1,4-dibromobenzene: In a three-necked flask equipped with a 1-liter mechanical stirrer, 16.7 g (73.0 mmol) of periodic acid and 525 ml of sulfuric acid were added. After the periodate was completely dissolved, 36.4 g (219 mmol) of potassium iodide was added in batches. The reaction mixture was cooled to -30°C, followed by the slow addition of 34.5 g (146 mmol) of 1,4-dibromobenzene over 5 min. The resulting mixture was stirred continuously at -25°C for 36 hours. Upon completion of the reaction, the mixture was poured into 2 Kg of ice and the solid product was collected by filtration. The solid was dissolved in chloroform and the organic phase was washed sequentially with 5% aqueous sodium hydroxide and deionized water, then dried with anhydrous magnesium sulfate. After concentration under reduced pressure, the residue was recrystallized by chloroform to give 36.0 g of white crystals (50% yield).1H NMR (CDCl3, 21 °C): δ = 8.02 (s, 2H). The 1H NMR spectrum was consistent with the data reported in the literature for 1,4-dibromo-2,5-diiodobenzene, confirming the successful synthesis of the target product.